Brake chamber -cut rod length / angle issue?

brake-school.com/bsrepo/video/VID-2020-013/properly_cut_ pushrod_clevis.mp4
The info you need starts at 1:35 but watch the whole video, about 6 minutes.
You should be able to shorten the rod on the truck without taking everything apart.
If you have dual chambers on the other axle you could measure the pushrod on those.
Use anti-seize on the clevis pins. They need to move freely for the slack adjuster to work and adjust the brakes.

 

Applied stroke is what they check. Standard 3030 chamber has 2.5 inches of stroke. With the brake applied there should be (if I'm remembering correctly) 1.5 inches of the stroke used and ideally there should be a 90 degree pushrod to slack adjuster angle.

 

In the video he uses 2". I would start with that and then see what the angle looks like with the brakes applied. He could not cut off much more than 2". The nut is against the chamber and there are not many threads left from the end of the rod to the nut.
Since your rod is already cut I would mark the ruler/square where the mark would have been and then mark 2 inches from that. Compare to the length of your rod now and then cut to get the 2" like in the video.
"My question about the 90 degrees was my main concern." I hear what you say about the angle. But if you use the spec then you can see where you end up and should be good
without guessing.
Bendix has a # for technical help. I'm sure Merritor does also. Call and ask them.

 

Attach a pic with both the brakes applied and released.

 

In the first pic it is obvious there is way too much rod and threads showing. If you had originally followed the method in the Bendix video you would have got it the first time, at least much closer than pic 1. Your pic 2 looks like what he ended up with in the video. Your method works and you ended up with the right result. However, there is nothing saying that the angle should be 90 degrees with the brakes applied or parking brake set. Selling the chambers with one length of rod and cutting allows one chamber to work for multiple applications. Kind of like universal. Universal is a bad word in my book and I always try to buy an exact fit to avoid modifications. Which is not possible with brake chambers.

 

You have to cut the rod, X amount, after marking the 90° mark based on length of slack adjuster.

 

Physics is saying exactly that. Maximum conversion of air pressure to braking force (well, technically brake cam torque) occurs when the rod is perpendicular to the slack.